Rock Products

JUL 2019

Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market

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28 • ROCKproducts • July 2019 www.rockproducts.com leading to frequent replacement and extra cost. The problem with these pumps is that they are composed mostly of hard metal and are capable of high flow rates. Usually this is desired. The faster a fluid can be pumped, the faster the job is done. However, in the case of abrasive fluids and fluids filled with particulates and solids, the pump only throws these solids against its metal harder and faster. This causes significant wear very quickly and can eventually com- promise the entire process. When considering dosing applications, centrifugal pumps are not an effective solution because they do not produce a precise flow and can shear fluids such as flocculants which reduces the efficiency and effectiveness of the dosing process. In many cases, to combat this problem in dosing, positive dis- placement pumps like hose pumps or diaphragm pumps are used instead. However, these pumps, while better at meter- ing, have pulsation and are not if not properly prepared to deal with damage, can lead to costly consequences. For instance, if the diaphragm or hose on these pumps breaks, the process fluid can be introduced directly into the atmosphere, resulting in dangerous or expensive leaks. Well-Designed Pumping Technology To address these problems plaguing the mining industry, companies can use pumps with slower operating speeds and more wear resistant construction materials. For exam- ple, NETZSCH pumps operate with a slower speed (typically around 100 to 700 rpm), so the particulates in the fluid don't hit or grind against the inside of the pump with as much force as they flow through. The rotors of their pumps turn in a soft elastomer stator. This creates a sort of pocket cavity for the fluid to pass through, keeping most of the solids in suspension instead of wear- ing the pump. When solids do come between the rotor and stator of the pump, the soft elastomer allows the metal rotor to compress the solid particles into the elastomer instead of grinding into them. Then as the rotor turns, the solids are released, re-enter suspension, and flow through the pump. Installing pumps such as these greatly increases efficiency and safety. Pumps that incur less wear last longer and require less replacement, allowing companies to save money on spare parts and replacement costs. This reliability also reduces the chances of catastrophic mechanical failure that can put employees at risk. Pumps with slower operating speeds can be operated with smaller motors. Centrifugal setups often require a booster pump and a second pump to achieve flow conditions such as a suction lift or when both a high flow and high pressure are required. In compari- son, this can be accomplished using just one progressive cavity pump to pull a suction lift and generate the required pressure or flow all in one pump. This allows mining companies to cut down on power consumption and the associated cost. Durable and reliable joints and parts combined with the cor- rect materials and construction get the best lifespan out of the pump and its various components. Matching the appropriate seals to these more efficient pumps completes the package and ensures the safety of everyone involved. This prevents any dangerous and contaminating leaks and/or loss of product. Extra accessories can further ensure safety, such as pro- tection to prevent pump damage due to running dry and pressure switches or release valves in the piping to prevent dangerously high pressures from building up. In the end, quality equals safety and efficiency. Compromis- ing with a slightly slower flow rate will increase the overall lifetime of mining equipment and save money on operating costs and replacements. A bit of attention to the appropriate seals and accessories will ensure the safety of the crew and the environment, pre- venting damage and potential lawsuits. Instead of running systems full throttle and then dealing with the consequences as they come, most operators will choose efficiency and qual- ity over speed and risk. S John Dean is a project manager for NETZSCH Pumps North America. Pumps

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